There are many producing advantages realized by monitoring and regulating performance of a well or series of hydrocarbon producing wells from a central monitoring station remote from the wells. One phase of such a system includes the use of a pressure monitoring apparatus which is communicated with each well. Thus, well pressure can be promptly transmitted by radio to the control station or base.
Apparatus utilized with such a system involves means for tapping into each well's main flow line at some point between the Christmas tree or the well head, and the pipeline which conducts the hydrocarbon fluid. In the event of breakage in the monitoring system, whether through inadvertence, accident or otherwise, it can be appreciated that a considerable amount of hydrocarbon fluid could escape into the atmosphere before corrective measures are taken.
It is known from experience, that the use of an excess flow valve in such an instance would function to cut off flow from a well in the event of a pressure monitoring system malfunction due to breakage or other mishap which fractures the fluid holding lines. Such an incident would normally necessitate a work crew going to the individual well to replace defective parts and to recommence production flow.
In the normal well monitoring operation, an excess flow valve is placed where it will automatically discontinue flow through the monitoring system upon indication that normal static conditions no longer prevail. Although the valve is automatically actuated to closed position, once the defect in the system or the damage is repaired, the valve cannot be readily readjusted to a normal open setting to recommence the monitoring operation.
In the present arrangement, there is provided such a valve which is capable of monitoring excess flow from a hydrocarbon producing well. The valve, as noted above, functions to automatically close in response to a situation wherein a predetermined, excessive volumetric flow of hydrocarbon is flowing through the valve. It further functions when closed, to provide means for automatically adjusting to open position when the downstream condition in the system has been repaired such that pressure monitoring can be continued.
This is achieved by permitting a downstream build-up in the well pressure downstream of the valve to occur through the use of a vent by-pass passage. The latter allows a minimal flow of the well fluid past the valve, which will then be forced into open position by spring pressure.
It is therefore an object of the invention to provide a pressure monitoring system for a producing well wherein an excess flow valve is included in the system to function in a manner that will permit automatically reactivating the system after the system excess flow control valve has closed.